- Mycoplasma gallicepticum is
thought to be the world's smallest
bacterium, with an average
diameter of 2.5 x 10-7 meter. The
largest bacterium is Thiomargarita
namibiensis, with an average diameter
of 2.0 x 10-4 meter. How many times
larger is Thiomargarita namibiensis
than Mycoplasma gallicepticum?